The present invention generally relates to ship navigation systems and more particularly to an acoustic system for determining the location of one's vessel within a channel on continental margins or within a harbor.
For the most part prior art devices have been buoys or lights within harbors and channels. Inclement weather raises obvious problems when one depends on such devices. On continental margins within the open sea electronic systems and celestial navigation have been utilized. Both of these require calculations not automatically provided from the sensing equipment. In addition celestial navigation also suffers from the problem of inclement weather. Other systems that provide electronic and acoustic signalling from fixed sources exterior to the vessel lack dependability and generally have undue complexity and cost in order to obtain the solution of the problem.